“Mass was so simple before you. Mass was just a property. Actually it was just a property of having another property: inertia. Inertia was so simple, though. It was just the property of resisting changes in motion.
Of course, we all know what ‘resisting’ means. And, we all know what motion is: d/t. If anyone must ask what distance and time are…well, there is little hope for someone so dim. At least, there is little hope for such a dimwit in physics. Hah! It looks like someone needs a metaphysician!”
The line of thought is a big hit with dualists. Actually, it is the best thing about mind/body dualism, and is why it’s good to have mind/body dualists around. Without them, physicalism grows too complacent.
The physicalist can be forgiven. It seems so obvious what we mean when we say that something is physical. But what does that mean? Is it simply anything that’s the proper business of physics? Is physics itself the proper business of physics?
The question of what makes something physical is actually difficult, even within physics. Take the Higgs field. It is not a ‘thing’; it is not even a ‘property’ of a ‘thing’. It is a property of space. It is a phenomenon which physics considers, but it is really weird, from the perspective of the old extended/unextended divide which Descartes proposed.
Yet we are prepared to accept the Higgs field as something physical, along with apples and atoms. That’s because we have been prepared to accept the physicality of the Higgs field by accepting the physicality of things like d and t in the Newtonian scheme, as physical. Time and distance are not any less weird – they are strangely malleable, for instance – but they are more easily recognizable as our own phenomena. We experience time and distance, and we are comfortable with the idea that physics is a phenomenology of time and distance.
If we have drilled down to the notion of physics as phenomenology, and understand phenomena as our experience, then the remaining question is: What is our experience? I am not sure there is an all-encompassing answer to that question. Yet I think we can say a few things around the question which are instructive as to the notion of physicality.
At base, our experience is identity, and identity is interdependence. If I am watching an egg roll off the counter and hit the floor, I am the one watching that egg. The rolling egg, among other things, is making me, me. The memories of eggs, dependent upon the shape, color, texture and historical context of my current experience, shape my thoughts and expectations regarding the egg, just as the color, shape and texture of the egg depend upon the impression that the kitchen light delivers to my eyes after it bounces off the rolling egg. That is what the notion of supervenience is getting at: identity is fixed by spatial and temporal history.
And such a thing cannot be ‘transcendent’. It comes with the here and now; (physical) existence has a tense. ‘Tenseless’ existence is a product of reflection and not what we directly experience. Transcendence, in other words, occurs in the storybook, not in the story (else we would never read a story twice).
The trouble with this whole picture is that it looks like a truism. If physicality consists of an interdependent identity which avoids transcendence, then what is left? Ghosts are live possibilities; so are Higgs fields. Of course, that is the point of physicalism. When we look at our experience in total, physicality seems to exhaust all the explanatory possibilities, or at least the ones we could hope to know.
Do we know anything at all?
Not much. Just enough.